I'm looking on Rockauto.com at like 7 different brands and I'd like some feedback... My rx7 has trouble starting when it's hot and it is fuel related. After like ten minutes of trying to start it after coming out of lowes today it finally idled and I drove away. I'm certain it is the fuel pump..23 years old after all. Fuel filter was changed a month ago.

 

1987 N/A btw

 

Hot start problems are not caused by fuel pumps. Read through this thread: https://www.rx7club.com/2nd-generation-specific-1986-1992-17/looking-car-has-hot-start-problems-499744/. The stock start map is excessively rich, which leads to flooding. A search for "deflood" or "flooding" will turn up many threads on the subject.

 

Check out the fuel strainer/sock.

 

hmm so it was flooded? that is why it wouldn't start immediately? It was trying to turn over as in it indicated not getting enough fuel but I guess you could be correct too. So when I fuel pump goes it just....goes and the car will not run at all after it goes??..

 

Check the o-ring on the pump outlet, and also the fuel sock as hypertek said.

 

If it only happens when the engine is already warm, and it starts/runs fine otherwise, I would not be looking to the fuel pump for the issue. A dying pump would create problems while the engine is running due to reduced flow and fuel pressure. If you want to confirm it's actually flooding, try to start it when warm, then pull the spark plugs. If they're wet with gas, that's a sign it's flooded. The "quick-fix" deflooding procedure is to pull the EGI fuses under the hood, crank for a few seconds, replace the fuses, then try to start it with the throttle open.

 

thats what I was thinking. I'll just pull the fuses next time. If I wanted to replace the pump as a precaution though which brand is FTW??

 

Bad compression will also give you hot start problems.

I've got a walbro 255 and i've had no problems, but a lot of people say they aren't good.

 

Walbro is not good for stock car because it flows way too much fuel. so instead of Super Rich Fuel trim, it becomes Uber Super Duper rich.

 

I had a hot start problem caused by the fuel pump o-ring. Here's how it works...

Start car cold, starts up great.

Start up warm, wouldn't start first try because PRC solenoid opens and lowers fuel pressure. I had no fuel pressure anyway because my o-ring was bad and all of ther fuel pressure was leaking back into the tank from the o-ring instantly.

 

you talking about the o-ring at the bottom of the assembly ?

 

Ya but I was running super lean before so the fuel pump evened it out perfect. The car rarely flooded

 

If you would like to rule out flooding being the issue. The next time it happens floor the gas peddle and crank it for 10 sec, let it sit for 5 sec, crank for 10, etc. (this works on my S5, not sure if it works on S4 models) This cuts the fuel and should allow it to deflood itself, and fire.

This works on RX8's as well, and is much easier than pulling plugs, atf, and all the other tricks.

A compression test wouldn't hurt either and is fairly simple to do, if you have someone to help.

 

^ Holding the pedal to the floor in an S4 won't cut fuel like an S5, but it will allow more air into the combustion chamber to hopefully start the engine. S4s just need the EGI fuses pulled to cut fuel.

 

Don't even consider an aftermarket fuel pump, especially a 255lph! N/A's run rich as it is, and that pump will only make the situation worse.

Leaking injectors might also play a part, but it really sounds like typical flooding issues here.

 

i dont mean to thread jack, but i have a related issue, i put an fd fuel pump to replace my stock n/a fuel pump on my t2 swap and ever since its struggled with cold and hot starts, but runs fine

 

Have you checked your fuel pressure?

 

the car died on a back road two days ago.. now it won't start at all. fuel pump must be dead.